Oil extended synthetic rubber compositions



Jan. 22, 1957 W. L. DUNKEL ETAL on. EXTENDED ssmmmc RUBBER cowosmons I 2 Sheets-Sheet 1 Filed May 27, 1953 TENSILE STRENGTH Columbiun o ComroI D Roffmufe Columbiun o 0 Extmcf Nuso I25 Burosu -43extrucr Diol s0 500-X Dlsfillclfe -Columbmn Distillate BurnhorI' MO. 0 Comm DISLQ -Nec1'on 60 l I l I 71, AR OMAT I 08 FlG.-l

WALTER L. DUNKEL C. DOWL ING INVENTORS ATTORNE Y positions.

United States Patent OIL EXTENDED SYNTHETIC RUBBER COMPOSITIONS Walter L. Dunkel, Roselle Park, and Francis P. Ford and William C. Dowling, Roselle, N. J., assignors to Esso Research and Engineering Company, a corporation of Delaware Application May 27, 1953, Serial No. 357,812

7 Claims. (Cl. 26033.6)

This invention relates to improved oil extendedsynthetic rubber compositions and relates more particularly to synthetic rubber compositions containing fractions of naphthenic crudes from which a large part of the arcmatics have been removed.

It is known to add naphthenic and aromatic hydrocarbon oils to natural and synthetic rubbers, such as GR-S or GR-I as plasticizers and extenders. These oils are good plasticizers and their low cost reduces the cost per pound of the finished rubber. Vulcanizates prepared from such oil-rubber compounds, for example, tire tread stocks, often possess wearing properties superior to those of vulcanizates produced from unextended, lower Mooney synthetic polymers.

The utility of a petroleum oil as an extender is determined by its physical and chemical properties. Not all oils are satisfactory. Thus, only oils containing less than 10-20% of constituents boiling below 700 F., at atmospheric pressure have sufficiently low volatilities to avoid excessive losses from the vulcanizates from use. Similarly, other thingsbeing equal, the viscosity of a preferred extender oil should be as low as possible for ease in factory handling.

on the properties of the oil-polymer compound ,and its vulcanizate.

In general, oils of high aromatic content impart good processing characteristics to the synthetic rubber com- These are accompanied by high tensile strengths. On the other hand the dynamic properties of the vulcanizates of oil-extended syntheticrubber compositions are adversely affected by highly aromatic oils.

Good processing characteristics and low hysteresis .are

both quite essential to the manufacture and use of tires, but these are not usually imparted to thepolymer by the same oil.

It has now been discovered that a refined petroleum oil which imparts both desired properties to a remarkable degree is obtained by extracting a heavy Colombian crude oil distillate with phenol.

Accordingly, therefore, the main object of the invention is the provision of natural and/or synthetic rubber compositions and particularly synthetic rubber compositions suitable for use as tire or tube stocks; for

molding purposes; for the fabrication of printers rolls,

hose, sheets, tubes, and other objects and specialties; for the preparation of adhesives and cements, and for coating, impregnating, waterproofing, and other specialized uses; comprising rubber, and particularly one or more syn- "ice 2 "Silica gel analysis:

Percent arom 35.65 Percent non-arom 64.35 H/C 1.78/1

The term rubber as used herein is intended to define a material which does not possess a definite and reproducible softening point, and which is capable of being vulcanized.

Rubber-has been defined in the prior art as follows:

A. An organic material which shows a high elasticity of 100 percent or more at room temperature and which does not lose this property upon storage at room temperature for considerable periods.

7 B. -A rubber is a substance which shows an elasticity of 800% or more with aquick return (snap) at temperatures at which natural rubber shows the same efiect "and which does not lose this property upon storage any sooner than does natural rubber.

C. In order to qualify as a rubber, a material should stretch readily to a considerable degree and after release retract forcefully and quickly. I

The following definition is preferred.

The term rubber is intended to embrace elastorners, whether natural or synthetic, and whether or not admixed with other ingredients such as pigments, softening agents, etc., in the vulcanized or unvulcanized state, the said elastomer being (1) capable of vulcanization such as by the application of heat when in admixture with sulfur or other vulcanizing agent, or otherwise, (2) slightly soluble or substantially insoluble in bodied drying oils such as bodied linseed oil, and (3) capable, either in the unvulcanized state or at some stage in the vulcanizationthereof, of being stretched readily to a considerable degree and, after release of the applied stress, retracting forcefully and quickly.

The synthetic rubber to which the extender oil is added includes neoprene, butadiene-styrene copolymers,

thetic rubbers, or elastomers, and 25 to 50 parts of the v ratfinate obtained by extracting a heavy Colombian crude with phenol. The rafiinatehas the following properties:

Aniline point (F.) ,.201.0

such as GR-S, butadiene-acrylonitrile copolymers, such as GR-N' and isobutylene-isoprene copolymers, such as GR-I with or without the incorporation of other additives selected from a list comprising sulfur, accelerators, pigments, resins, antioxidants, fillers, extenders, and/or other plasticizing and/ or softeningagents, such as stearic acid, pine oil, and pine tar.

The advantages of the invention will be better understood from a consideration of the following experimental data which are given for the sake of illustration,'but without intention of limiting the invention thereto:

The following petroleum oil extenders were prepared: Necton-60Phenol extract of a naphthenic distillate. Nusol25-A Phenol extract of a coastal crude distillate. 500 distillate-Distillate of a coastal crude. Earnhardt motor oil distillate-Motor oil distillate fraction from a Texas crude.

Roxtone l-Distillate of a heavy naphthenic Colombian crude. Barosa-43XTPhenol extract from a mixed base of Gulf Coast crude.

C-22 Aromatic OilThe aromatic oil fraction from thermal cracking of the heavy ends obtained by catalytic cracking of virgin gas oil from Texas crude.

Process Oil #l--Phenol extract of a motor oil distillate from a- Texas crude. Circosol2XH.Commercial oil. obtained from the Sun Oil Company. Control- CSame as Circosol 2XH.

Control D-Commercial oil obtained from the Shell Oil Company. SPX- 97 Commercial oil obtained. from the Shell Oil Company.

,fBaro'sa v,X56A phenol extract from a mixed base gulf Patented Jan. 22, 1957' e1 4 coast crude having a higher viscosity than Barosa tested for dynamic properties. The following results 43XT. were obtained: Center side stream-Is the center side stream from the fractionation of phenol extract from heavy Colombian Gircoso1 901mm Earnhardt di ill m 5 2XH Rbian t Motor Oil Diol 80-An acid-treated naphthenic distillate. afina e Dist Colombian distillateDistillate from a Colombian crude.

Aromaticity percent 43 35. 6 26. 3 Colombian rafiinate-Raifinate from phenol extraction of stresastmm Properties:

1 Modu] 300 900 880 1,070 Colomblan dlsunate' 'rensiie en tizi 2,680 2, 490 2,750

10 Dynamic Properties 50 0.. EXAMPLE I Relative Damping percent.. 26.0 25.5 25.5 Dynamic Modulus 3. 17 2. 94 3. 03 These extenders had the following inspections: flfintemalfmtlon) M0 Table 1A INSPECTIONS ON PETROLEUM OIL EXTENDERS Necton 500K Earnhardt O 22 Inspection 60 Nuso 125 Dist. Motor Oil Roxtone 180 Burosa 43Xl Aromatic Distillate Oil Boiling Range (F.) 002+ 048+ 738+ 745+ 824-977 (23%) 585+(5%, 684) 700-900 Refractive Index". 1. 4920 1. 5481 1. 5080 1. 4952 1. 5221 1. 5327 S ec. Gravity 0.89 0.95 0. 92 0.89 0. 944 I 0.95 Aniline Pt. (F.) 214. 9 103. 1 191.1 219. 4 200. 1 133. 3 111. 0 Iodine No. (cg /g) 11. 9 25. 5 17. 0 15. 4 23. 9 20. 0 34.1 Vol. (perce t 0. 051 0.087 0.024 0.004 0.00 0.45 0.204 Viscosity:

100 F 508.2 950. 8 538 6828.4 287.1 981. 8 210 58.08 149. 9 67.85 61.68 177.8 47. 4 55. 82 Viscosity Index. 63. 5 26. 8 78. 6 -27. 3 38. 5 1l() Pour Pt. (F. -i0 45 5 70 90 Flash Pt. (F.) 445 435 435 460 545 390 410 Silica Gel Analysis:

Percent Areni 21. 74. 5 35. 75 20.35 50. 5 07. 71 75. 85 Percent Non-Arom 78. 75 25. 3 63. 25 73. 65 49. 4 32. 29 21. 15

(-)short Path dist. )3 hrs. 134 0. )Cleveland open cup.

Table 1B INSPECTIONS ON PETROLEUM OIL EXTENDERS Inspection 00]. Dist. Colombian 001. KT Diol 80 Process Cricosol 2XH Control 0 Control Raifinate Oil #1 D Boiling Range F.) 500-977 (82%) 608-977 (81%) 671-977 (84%) 544+ 680-980 711+ (5% 770) 047+(5% 700) 045+ Refractive Index 1.5149 1.5005 1.5541 1. 5052 1.5583 1.5217 1. 552 1. 0035 Spec. Gravity 0. 94 0. 91 0. 99 0. 91 0. 974 0. 94 0. 97 1. 03 Aniline Pt. F.) 177. 4 201. 0 94.5 204. 0 105 181 130 2. 3 Iodine No. (era/g.) 21. 5 17.8 29. 4 18.1 30. 4 20. 7 27. 4 24. 5 $111. (Pgrcent Wt. Loss) 0. 58 0.12 0.14 0.043 0.089 0.046 0.254 0.14

100 F 931. 5 728. 5 5,289. 9 2. 034 210 F 66. 73 54.19 110. 0 91. 9 91. 9 81. 5 82. 52 23.1 Viscosity Index" 22. 8 48. 5 -101 38. 2 Pour Pt. F.) -15 15 20 20 5 00 Flash Pt. F.) 375 420 420 455 455 430 405 405 Silica Gel Analysis:

Percent Arom 45.0 35. 65 76.4 39. 9 81. 4 43.0 72. 5 93. 42 Percent N on-Arom 55.0 64. 35 23. 6 1 18 6 57.0 27. 5 6. 58

(I) Short path dist. 5 03 hrs. 134 C.

Cleveland open cup.

EXAMPLE II Three of the foregoing Oils wars mixed in an open The above data clearly show that Colombian ratfinate laboratory mill in accordance with the following recipe: lmp rt the es I ternal frlc lon t0 the GR-S.

Parts by weight 100 EXAMPLE III Oil 50 C b bl k 7 Twelve of the 011s of Example I were mixed 111 a #00 Zinc oxide 5 laboratory Banbury mill in accordance with the recipe of Sulfur 2 Example II, and tested for processing characteristics as BLE stabilizer 1 observed by visual appearance, tensile strength and ex- Curing aid (Santocure) 1 tension swell. The data are reported in Tables 1A and The mixture was cured for 60 minutes at 287 F. and 75 1B and Figures 1 and 2.

Colombian Dist.

Bernhardt Motor Oil Distillate Necton-BO' Control -D N new 125 Diol 50-X "Dist.

"2;7 7S, 8iO8 .Table 2A PROCESSING STUDY Barosaiii-Ext.

Table 2B PROCESSING STUDY Colombian Raifinate Control 0 Colombian Extract 212 1 Extrusion Proncrties .22

ss (aged 48 hrs. 21

Prop. 50 C. (orig nal-agcd): nt R. D.

sit i Extrusion Properties 220- F Wt'fii] "WE HcLUSE (2592i ie 111 510 erce 3 ct Grams per min- Grams per inch Reltgpe: (Banbury mix) High Mooney GBS1,000; 'HAF Black-750; Oil-500; BLE-IO; Zinc Oxide-50; Sulfur-20; Santo- 'cure- Y Grams per inch Cc./i

Percent R. D.-

P Dyn. Mod

1 X10' Mooney Visco 'Cc./i .Perce amic Force ,Relgpez (Banbury'mix) High Mooney GR-S1,000; HAF Black-750; Oil500; BLE10; Zine 0xide-00; Sulfur-20; Santocure-'- ."Bercent Aromatic.-. Stress-Strain Pro Stress-Strain Prop. (orig-aged 'Iens1le Elong Dynamic Prop D-Dynamic Percent Aromatic...

0000 1 o m anon mus m 1 8 v 5 2 12 2 P 0 0000 557 6 679 4 M W W 262% %24 2 O 1 1 m 2 000 n 730 4 0 L mum H 1 3 m6 2 1; 1 N 1 0 7 O 0 9 7%wm 4 2741 636 1 I 2 v 7 1 v 2 I 12 I P S 8 H 0 0000 a 1 0097 T o o 3727 n 1 1 11 H2 0 n SJ m mwF c n h H .fim aa 01 P an 2 s m m m PmM dt 0h t o ma am w rm mwYX hP l PD WW o v t PS D 0 r0 0 6 6 7 For EXAMPLE IV Five of the oils of Example I were compounded according to Example II in such a way as to produce a relatively poor pigment dispersion.

A portion of each batch was remilled to improve the dispersion. The data are reported in Table III. 75

The above data indicate that even under such conditions of preparation the Colombian raftinate imparts a unique combination of good processing and good dynamic properties to the GR-S composition. The internal viscosity is 4, 7, and the dynamic modulus is 2.5, the lowest of the five oils, while the tensile is 2225, surprisingly high for the aromatic content of the oil.

The nature of the present invention having been thus fully set forth and specific examples of the same given, what is claimed as new and useful and desired to be secured by Letters Patent is:

1. A composition of matter comprising a rubber and a plasticizing amount of an extender oil consisting of a raflinate having approximately the following properties:

Boiling range F 668-977 (81%) Specific gravity 0.90-0.92 Aniline point F 190-210 Iodine No. (cg./g.) 16-20 Viscosity (SSU at 100 F.) 700-750 Percent aromatics 30-40 Pour point F to -30 Viscosity index 40-55 said raffinate having been obtained by the phenol extraction of a Colombian crude oil distillate having approximately the following properties:

Boiling range P... 500-977 (82%) Specific gravity 0.92-0.96 Aniline point F 175-180 Iodine No. (cg./ g.) 21-22 Viscosity (SSU at 100 F.) 900-950 Percent aromatics 40-50 Pour point F 0 to -30 Viscosity index 20-25 2. A composition comprising a synthetic rubber selected from the group consisting of butadiene-styrene copolymers, butadiene-acrylonitrile copolymers, neoprene, and isobutylene-isoprene copolymers and about 25-50 parts by weight based on 100 parts by weight of total composition of an extender oil consisting of a ratfinate having approximately the following properties:

Boiling range F 668-977 (81%) Specific gravity 0.90-0.92 Aniline point F 190-210 Iodine No. (cg/g.) 16-20 Viscosity (SSU at 100 F.) 700-750 Percent aromatics 30-40 Pour point F 0 to -30 Viscosity index 40-55 said raffinate having been obtained by the phenol extraction of a Colombian crude oil distillate having approximately the following properties:

Boiling range F 500-977 (82%) Specific gravity 0.92-096 Aniline point F 175-180 Iodine No. (cg./ g.) 21-22 Viscosity (SSU at 100 F.) 900-950 Percent aromatics 40-50 Pour point F 0 to -30 Viscosity index 20-25 3. Composition according to claim 2 which further contains a minor proportion, based on the total composition of a pigment, zinc oxide and sulfur.

4. A composition of matter comprising about 50-75 parts by weight of a synthetic rubbery copolymer of butadiene with styrene and about 25-50 parts by weight of an extender oil consisting of a raflinate having the following properties:

Boiling range P... 668-977 (81%) Specific gravity 0.90-0.92 Aniline point F-.. 195-205 Iodine No. (cg./g.) 17-19 Viscosity (SSU at F.) 710-740 Percent aromatics 30-40 Pour point F 0 to -30 Viscosity index 45-50 said rafiinate having been obtained by the phenol extraction of a Colombian naphthenic crude oil distillate having approximately the following properties:

Boiling range P... 500-977 (82%) Specific gravity 0.93-0.95 Aniline point F -180 Iodine No. (cg./ g.) 21-22 Viscosity (SSU at 100 F.) -2 900-950 Percent aromatics 42-48 Pour point F 0 to -30 Viscosity index 20-25 Boiling range F 668-977 (81%) Specific gravity 0.90-0.92 Aniline point F -205 Iodine No. (cg./ g.) 17-19 Viscosity (SSU at 100 F.) 720-740 Percent aromatics 33-38 Pour point F -10 to -20 Viscosity index 47-50 said rafiinate having been obtained by the phenol extraction of a Colombian crude oil distillate having approximately the following properties:

Boiling range F 500-977 (82%) Specific gravity 0.92-0.96 Aniline point F..- 175-180 Iodine No. (cg/g.) 21-22 Viscosity (SSU at 100 F.) 900-950 Percent aromatics 40-50 Pour point F 0 to -30 Viscosity index 20-25 7. Composition according to claim 6 in which the rubber is a copolymer of butadiene and styrene, the composition further containing a small amount of a curing aid.

References Cited in the file of this patent UNITED STATES PATENTS McMillan Ian. 15, 1952 OTHER REFERENCES Rostler: Rubber Age, 63, 317-326, June 1948. Rostler: Ind. Eng. Chem., 41, 598-608, March 1949. DIanni: Rubber Age, 317-321, June 1951.

Kurtz: India Rubber World, 126, 495-499, July 1952. 

1. A COMPOSITION OF MATTER COMPRISING A RUBBER AND A PLASTICIZING AMOUNT OF AN EXTENDER OIL CONSISTING OF A RAFFINATE HAVING APPROXIMATELY THE FOLLOWING PROPERTIES: 